PhET provides fun, free, interactive, research-based science and mathematics simulations. We extensively test and
evaluate each simulation to ensure educational effectiveness. These tests include student interviews and observation of
simulation use in classrooms. The simulations are written in Java, Flash or HTML5, and can be run online or downloaded
to your computer. All simulations are open source (see our source code).
Multiple sponsors support the PhET project, enabling these
resources to be free to all students and teachers.

Create a simulation that can be flexibly used in many educational situations

Several tools in the simulations provide an interactive experience:

Click and drag to interact with simulation features

Use sliders to increase and decrease parameters

Choose between options with radio buttons

Make measurements in your experiments with various instruments – rulers, stop-watches, voltmeters, and thermometers.

As users interact with these tools, they get immediate feedback about the effect of the changes they made.
This allows them to investigate cause-and-effect relationships and answer scientific questions through exploration of the simulation.
For more information, visit our research page.